Sternal ascender apparatus

ABSTRACT

A sternal elevator apparatus is disclosed. The sternal elevator may include a panel, a support beam traversing the panel, and a post coupled to a proximal end of the panel. The apparatus may also include an indicator handle coupled to the sternal elevator, an actuator drive pivotably coupled to the indicator handle, and a housing movably coupled to the actuator drive. The sternal elevator apparatus may have an actuator drive incorporating a linear rack. The housing further may include a cylindrical gear where the cylindrical gear is engaged with the linear rack.

REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation of U.S. patent applicationSer. No. 16/999,838, filed Aug. 21, 2020, which claims priority to U.S.Provisional Patent Application No. 62/889,690, filed Aug. 21, 2019, U.S.Provisional Patent Application No. 62/916,591, filed Oct. 17, 2019, andU.S. Provisional Patent Application No. 62/989,044, filed Mar. 13, 2020,each of which is hereby incorporated by reference in its entirety.

FIELD

The claimed invention relates to minimally invasive surgical devices,and more specifically to a surgical device used in increasing operablespace during minimally invasive surgical procedures.

BACKGROUND

Minimally invasive surgical approaches are gaining increased interest inrelation to coronary procedures. Coronary revascularization proceduressuch as the grafting of the internal thoracic artery (ITA) has shownsuperior long-term patency and improved patient outcome in coronaryartery bypass graft (CABG) surgeries. While conventional approaches toITA harvesting have included median sternotomy or multiple thoracoports,a minimally invasive approach is desirable. A minimally invasiveprocedure related to revascularization using either the left or rightinternal thoracic artery (ITA), or the left or right internal mammaryartery (IMA) may utilize access to the ITAs via sub-xiphoid access,where increased surgical space is gained by accessing the internalthoracic arteries via incision at the subxiphocostal region.

Upon harvesting either the left internal thoracic artery (LITA) or theright internal thoracic artery (RITA) anastomoses to the left anteriordescending (LAD) coronary artery and to the right coronary artery (RCA),respectively, can be performed without cardiopulmonary bypass (CPB). Asignificant advantage of this approach is that a perfectly harvested ITAgraft can be perfectly anastomosed to the usual site on the LAD artery,or onto the RCA artery. A minimally invasive ITA harvesting procedureinvolving sub-xiphoid access also results in superior cosmetic results,is reasonably painless, and the arterial grafting can be accomplished onthe beating heart. Recent approaches of minimally invasive ITAharvesting surgical techniques have been shown to result in increasedeffective length of ITA bypasses, reduced operation times, and improvedpatient recovery.

While less invasive surgical approaches for ITA harvesting and CABG haveshown promise, visualization, maintenance of insufflation, and distalsuturing of a coronary anastomosis in totally endoscopic coronary arterybypass grafting on the beating heart is technically demanding. There isa need for larger working spaces to accommodate an increased range ofmotion during surgical procedures, as well as room for additionalsurgical tools, such as endoscopes, suturing tools, and the like.However, achieving an increased working space should ideally preservechest wall integrity and avoid CPB. Likewise, a minimally invasivesurgical approach should not compromise the reliability of a cardiacrepair.

Therefore, there exists a need for minimally invasive surgical devicesand methodology applicable to ITA harvesting and other surgicalprocedures such as epicardial lead placement and others that increaseoperable space for harvesting and anastomosis and other surgicalprocedures, reduce operating time, and improve patient outcome duringminimally invasive cardiac procedures and other surgical procedures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top-front-right perspective view of one embodiment of asternal ascender apparatus with a right sternal ascender attached.

FIGS. 2A-2E is a series of exploded views illustrating the apparatus ofthe sternal ascender apparatus of FIG. 1 .

FIG. 3 is a perspective view of a left sternal ascender.

FIGS. 4A, 4B, 4C, 4D, 4E, and 4F are front, left side, right side, rear,top, and bottom elevational views, respectively, of the sternal ascenderof FIG. 3 .

FIG. 5 is a perspective view of a right sternal ascender.

FIGS. 6A, 6B, 6C, 6D, 6E, and 6F are front, left side, right side, rear,top, and bottom elevational views, respectively, of the right sternalascender of FIG. 5 .

FIGS. 7A-7C are a series of perspective views illustrating operationalsteps showing the loading of the left sternal ascender of FIG. 5 intothe sternal ascender apparatus of FIG. 1 .

FIG. 8 is a perspective view of a surgical setting including the use ofthe sternal ascender apparatus of FIG. 1 .

FIGS. 9A-9D are a series of perspective views illustrating operationalsteps of the use of the sternal ascender apparatus in a surgicalcontext.

It will be appreciated that for purposes of clarity and where deemedappropriate, reference numerals have been repeated in the figures toindicate corresponding features, and that the various elements in thedrawings have not necessarily been drawn to scale in order to bettershow the features.

SUMMARY

A sternal ascender apparatus is disclosed. The sternal ascender mayinclude a panel, a support beam traversing the panel, and a post coupledto a proximal end of the panel. The apparatus may also include anindicator handle coupled to the sternal ascender, an actuator drivepivotably coupled to the indicator handle, and a housing movably coupledto the actuator drive. The sternal ascender apparatus may have anactuator drive incorporating a linear rack. The housing further mayinclude a cylindrical gear where the cylindrical gear is engaged withthe linear rack.

Another sternal ascender apparatus is disclosed. The sternal ascendermay include a panel having a plurality of textural features, a supportbeam traversing the panel, and a post coupled to a proximal end of thepanel. The apparatus may also include an indicator handle removablycoupled to the sternal ascender, an actuator drive pivotably coupled tothe indicator handle having a linear rack, and a housing movably coupledto the actuator drive having a cylindrical gear and two instrumentadapters.

DETAILED DESCRIPTION

FIG. 1 is a perspective view of one embodiment of a sternal ascenderapparatus with a right sternal ascender attached. An embodiment of asternal ascender apparatus 10 is shown in FIG. 1 , with a right sternalascender 12 installed therein. The right sternal ascender 12 defines apanel 14, the panel 14 having several textural features 15 configured toprovide an atraumatic yet firm grip on the underside of a ribcage whenthe sternal ascender assembly 10 is in use in a minimally invasivesurgical procedure. The panel 14 of the right sternal ascender 12 alsodefines a notch 16 and has a support beam 18 on the underside of thepanel 14 The right sternal ascender 12 has a mounting post 20 on aproximal end 12P. The mounting post 20 is coupled to a proximal end 22Pof an indicator handle 22 at the end of the mounting portion 24 of theindicator handle 22. The right sternal ascender 12 is coupled byreversible means such that the right sternal ascender 82 may be easilyremoved and replaced with a left sternal ascender, which is not shown inthis view. The term ascender may be used interchangeably with the termelevator or lifter, as they equivalently describe the intended functionof the ascender and associated apparatus. This coupling means will bedescribed in further detail later. One alternate example of a couplingmethod is using a set screw, although others may be known to thoseskilled in the arts. The indicator handle 22 further defines a grip 26in the underside of the indicator handle 22, which is configured for anergonomic gripping feature for the comfort of use by a surgeon. At adistal end 22D of the indicator handle 22 is a connection end 28 and apressable switch 30. Towards the distal end 22D of the indicator handle22 is a depth indication mark 27, which is vertically aligned with thedistal end 12D of the right sternal ascender 12. The connection end 28is a coupling point that accepts a corresponding connection end 32 on alinear rack or linear actuator gear 34 by way of mating with theconnection end 28 and is pivotably attached by joining a pivot pin 40 oralternatively by other attachment means into a hole or other attachmentmeans not shown in this view. The pressable switch 30 can be pressed oractuated to defeat a pawl that is located inside the indicator handle22, but not shown in this view. The pawl interfaces with a fixedindexing gear located inside the connection end 32 portion of the linearactuator gear 34. This will be discussed later in more detail in regardto FIGS. 2A-2E. The pawl defines a spring or biasing element to bias,while at rest, one or more teeth defined by the pawl toward the fixedindexing gear, which is not shown in this view but is coupled to theconnection end 32 of the linear actuator gear 34. When the one or moreteeth on the pawl intermesh with one or more corresponding teeth orother locking feature defined by the fixed indexing gear, this locks theangular position of the linear actuator gear 34 relative to the positionof the indicator handle 22. When switch 30 is pressed or actuated, thepawl is defeated and temporarily pushed away from the fixed indexinggear, allowing free angular movement of the linear actuator gear 34relative to the indicator handle 22. Releasing the switch 30, re-engagesthe pawl and the fixed indexing gear to once again interface and lockthe angular position of the linear actuator gear 34 relative to theindicator handle 22 that it was in when the switch 30 was released.

The linear actuator gear 34 further defines several teeth 36 and severalrecesses 38 that engage a cylinder gear 122. The linear actuator gear 34fits through an actuator slot 42 in a dual side instrument adapter 44.The dual side instrument adapter 44 defines a first adapter channel 46and a second adapter channel, not visible here, on the opposite side.The dual side instrument adapter 44 also defines several lockingmechanisms 100, 102 for locking the dual side instrument adapter 44 intoa surgical equipment holder on each side. Once the dual side instrumentadapter 44 is attached on each side to a surgical equipment holder, itcan be positioned over a patient by bridging two surgical equipmentholders across a surgical table. Other embodiments may only have asingle adapter channel for mounting onto a single surgical equipmentholder. Attached to the dual side instrument adapter 44 is a gearhousing 48 which holds the cylinder gear 122. A handle or swivel bar 50is coupled to the cylinder gear 122. Turning the handle 50 rotates thecylinder gear 122 and thereby moves the linear actuator gear 34 back andforth which forms an actuator drive. In this embodiment, the sternalascender assembly 10 is inserted into an incision below the sub-xiphoidof a patient undergoing a minimally invasive surgical procedure, such asan ITA harvesting procedure or other surgical procedure in whichincreased access space below the sub-xyphoid process is advantageous.The panel 14 of the right sternal ascender 12 can be used to enablelifting the ribcage, thereby increasing space in the subxiphoid area.One feature of the sternal ascender assembly 10 is that the length ofthe distal end 22D of the indicator handle 22 is substantially the sameas the length of the right sternal ascender 12 panel 14, which providesthe surgeon with a visible indication, along with the depth indicationmark 27 of how far the right sternal ascender 12 or the right sternalascender (if installed into the sternal ascender apparatus 10) has beeninserted into the subxiphoid cavity of the patient. The distal end 22Dof the indicator handle 22 is substantially aligned with a distal end12D of the sternal ascender 12. The indicator handle 22 is alsosubstantially parallel to the panel 14 of the right sternal ascender 12or the panel of a right sternal ascender. Once the sternal ascenderapparatus or assembly 10 is inserted into the subxiphoid cavity, thesternal ascender assembly 10 is attached to one or more surgicalequipment holders, enabling stability of force throughout a minimallyinvasive surgical procedure. Further adjustments to the position of thesternal ascender assembly 10 may then be made by pivoting about thecoupling joint of the indicator handle 22 and the linear actuator gear34. The sternal ascender assembly 10 can be further adjusted by rotatingthe swivel bar 50 and actuating the linear actuator gear 34 in a distaldirection. This operation will be discussed in further detail later.

FIGS. 2A-2E is a series of exploded views illustrating the assembly ofthe sternal ascender apparatus of FIG. 1 . As illustrated in FIG. 2A, afirst handle half 22A defines a recess or channel 52 having a mountingslot 54 and a seat 56. The mounting slot 54 and seat 56 defined by thechannel 52, also referred to as a t-slot based on the general shapethereof, are configured to removably receive an alignment key on thepost of either a left or right sternal ascender. A second handle half22B also defines a corresponding recess, not shown in this view. Thefirst handle half 22A also defines a second recess 72 at an opposite endand a gear recess 74 and hole 76. The second handle half 22B alsodefines a corresponding recess, not shown in this view. The secondrecess 72 is configured to receive and hold a spring 58, spring plunger60, and plunger housing 62, which are first assembled together. A pawlgear 64 having gears 66 and an ungeared portion 65 and a fixed indexinggear or a pivot gear 68 having a gear keyway 70 are placed into hole 76and held in gear recess 74, respectively, on the first handle half 22A.The pawl gear 64 is held against the spring 58, spring plunger 60, andplunger housing 62 assembly such that the pawl gear 64 is biased againstthe pivot gear 68 until the pawl gear 64 is depressed to slide the pawlgear 64 so that the gears 66 are disengaged from the pivot gear 68 suchthat it interfaces with the ungeared portion 65 of the pawl gear 64,thus allowing free rotation or pivoting of the pivot gear 68. When thepawl gear 64 is released, the gears 66 relock with the pivot gear 68preventing further pivoting or rotation of the pivot gear 68. The secondhandle half 22B is then placed over the first handle half 22A andfastened using several rivets 90 which are placed and fixed into holes84, 86, 88 on the second handle half 22B. While holes and rivets areused here to fixedly attach the handle halves 22A, 22B together,welding, adhesives or other means known to those skilled in the art mayalso be employed.

FIG. 2B illustrates the assembly of an instrument adapter assembly 116portion of the sternal ascender apparatus 10. A first adapter housing 92having several holes 95 and side hole 97 is assembled by placing a firstcam 96 having a flat 96F into hole 97. A first lever lock 100 having akey 104 is placed into hole 97 and into the first cam 96 such thatrotating the first lever lock 100 will also rotate the first cam 96within hole 97. The first lever lock 100 is pivotably attached to thefirst adapter housing 92 with the use of rivet 108 being placed intochannel 106 on the first lever lock 100. A second adapter housing 94having several holes 95 and side hole, not visible here, is assembled byplacing a second cam 98 having a flat 98F into hole 97. A second leverlock 102 having a key 110 is placed into a hole on the second adapterhousing 94 and into the second cam 98 such that rotating the secondlever lock 102 will also rotate the second cam 98 within the hole in thesecond adapter housing 94. The second lever lock 102 is pivotablyattached to the second adapter housing 94 with the use of rivet 114being placed into channel 112 on the second lever lock 102.

FIG. 2C continues the assembly of the sternal ascender apparatus 10focusing on the linear actuator gear 34. The linear actuator gear 34,having a connection end 32 which further defines a hole 136 and severalteeth 36 with several recesses 38 positioned therebetween. A cylindergear 122 defines two sides 130, a side channel 128 on either side 130, aslot 124, and two posts 126, one of which is visible here, is placedinto the linear actuator gear 34 with the two posts 126 held in twoadjacent recesses 38. A drive bottom 134 is fixed with two rivets 132onto the two posts 126 of the cylinder gear 122 on the opposite side ofthe linear actuator gear 34. Once fully assembled, the cylinder gear 122is rotated in a clockwise or counterclockwise direction this therebymoves the linear actuator gear back and forth forming an actuator drive.As the cylinder gear 122 is rotated, the first pinion or post 126 willrotate out of a recess 38 on the linear actuator gear 34 and outwardwhile the second pin driver (not visible here) remains in a secondrecess 38 and rotates within the second recess 38. The first post 126will rotate into a third recess 38, past the second recess 38 thustranslating rotational motion into linear motion and moving the linearactuator gear 34 relative to the gear housing 48. Performing thisoperation in the reverse will move the actuator gear 34 in the reversedirection. A upper rack housing 48 having a central opening 120 andseveral holes 118 is then placed over the linear actuator gear 34 andcylinder gear 122 so that the cylinder gear 122 protrudes from thecentral opening 120 of the upper rack housing 48 and the upper rackhousing 48 is able to slide along the linear actuator gear 34 as thecylinder gear 122 is rotated. FIG. 2D illustrates the handle 50 beingplaced into the cylinder gear 122 between the two sides 130 and held inplace by placing a rivet 119 through the side channels 128 on thecylinder gear 122 and through the hole 138 on the swivel bar 50. Amiddle rack housing 140 having a central hole 142, several holes 144,and two housing inserts 146 is placed onto the bottom of the linearactuator gear 34 to align with the upper rack housing 48. The holes 118on the upper rack housing 48 are aligned with the holes 144 on themiddle rack housing 140. The two housing inserts 146 are configured tohold captive and allow free rotation of the drive bottom 134 of thecylinder gear 122. The handle or swivel bar 50 is used to swivel androtate the cylinder gear 122 during operation. The assembly of thesternal ascender apparatus 10 is completed in FIG. 2E by inserting thedistal end 22D of the indicator handle 22 into the linear actuator gear34. The pivot pin 40 is inserted into hole 136 with the pivot pin post148 interlocking into the gear keyway 70 of the pivot gear 68, thefunction of which was illustrated in FIG. 2A. The instrument adapterassembly 116 shown and described in regard to FIG. 2B is placed onto thebottom of the middle rack housing 140 and holes 95 in the instrumentadapter assembly 116 are aligned with the corresponding 118 holes in theupper rack housing 48. Several rivets 150 are then placed into the holes118 to fixedly join the instrument adapter assembly 116 to the middlerack housing 140 and upper rack housing 48.

FIG. 3 is a perspective view of a left sternal ascender. This viewillustrates the various features defined by the left sternal ascender152. The left sternal ascender 152 defines a panel 154 having severaltextural features 156, a contralateral, or pertaining to the oppositeside of targeted anatomical area, notch 162 at a proximal end 152P, asupport beam 160 traversing the underside of the panel 154, and amounting post 158 for attachment to a sternal ascender apparatus. Thepanel 154 has a rounded shape with a slight edge at a distal end 152D ofthe panel 154 of the left sternal ascender 152. Also defined by the post158 are two opposing alignment and orientation features 164 configuredto align, slide and lock the left sternal ascender 152 into the handle.These features 164 form a general t-shape, which are configured to fitinto the aforementioned t-slot on the indicator handle 22. The use ofthis feature will be described further in regard to FIGS. 7A-7C. Thepost 158 also defines an angular front alignment feature 166 which isused to help align and place the left sternal ascender in an anatomicalnotch defined between a rib and sternum. This can serve as a tactileassist in placing the sternal ascender in an appropriate place when inuse as part of a sternal ascender apparatus. While the embodiment shownhas these characteristics, alternate embodiments of a sternal ascenderpanel may have other shapes or radiuses, and may or may not besharpened. Still other embodiments may have other features aside fromthe rectangular textural features 156 shown here, and may include othershaped features or none at all. Other embodiments of left sternalascenders may be made of metal, plastic, composites, or mixtures orconbinations thereof or contain alternate alignment or locking methodsand features. FIGS. 4A, 4B, 4C, 4D, 4E, and 4F are front, left side,right side, rear, top, and bottom elevational views, respectively, ofthe sternal ascender of FIG. 3 .

FIG. 5 is a perspective view of a right sternal ascender. This viewillustrates the various features defined by the right sternal ascender12. The right sternal ascender 12 defines a panel 14 having severaltextural features 15, a contralateral, or pertaining to the oppositeside of targeted anatomical area, notch 16 at a proximal end 12P, asupport beam, not shown here, traversing the underside of the panel 14,and a mounting post 20 for attachment to a sternal ascender assembly.The panel 14 has a rounded shape with a slight edge at a distal end 12Dof the panel 14 of the right sternal ascender 12. Also defined by thepost 20 are two opposing alignment and orientation features 168configured to align, slide and lock the left sternal ascender 12 intothe handle. These features 168 form a general t-shape, which areconfigured to fit into the aforementioned t-slot on the indicator handle22. The use of this feature will be described further in regard to FIGS.7A-7C. The post 20 also defines an angular front alignment feature 170which is used to help align and place the left sternal ascender in ananatomical notch defined between a rib and sternum. This can serve as atactile assist in placing the sternal ascender in an appropriate placewhen in use as part of a sternal ascender apparatus. While theembodiment shown has these characteristics, alternate embodiments mayhave other shapes or radiuses, and may or may not be sharpened. Stillother embodiments may have other attachment features aside from therectangular textural features 15 shown here, and may include othershaped features or none at all. Other embodiments of right sternalascenders may be made of metal, plastic, composites, or mixtures orconbinations thereof. FIGS. 6A, 6B, 6C, 6D, 6E, and 6F are front, leftside, right side, rear, top, and bottom elevational views, respectively,of the right sternal ascender of FIG. 5 .

FIGS. 7A-7C are a series of perspective views illustrating operationalsteps showing the loading of the left sternal ascender of FIG. 5 intothe sternal ascender apparatus of FIG. 1 . The appropriate sternalascender, left or right, is selected depending on the area of interestfor a minimally invasive surgical procedure requiring the sternum of apatient to be lifted upward. FIG. 7A shows the right sternal ascender 12aligned with and in proximity to the t-slot 54 of the indicator handle22 of the sternal elevator apparatus 10 with the orientation features168 on the post 20 of the right sternal ascender 12 moved towardsdirection 169 and fully inserted into the slot 54 of the indicatorhandle 22. Once inserted, as shown in FIG. 7B, the right sternalascender 12 is pulled downward in direction 171 towards the seat 56 inthe slot 54 of the indicator handle 22 to lock the right sternalascender 12 into place. FIG. 7C shows the fully inserted and lockedright sternal ascender 12 in the indicator handle 22.

FIG. 8 is a perspective view of a surgical setting including the use ofthe sternal ascender apparatus of FIG. 1 . In the illustrated surgicalsetting, an operating table 174 having a rail 176 and a patient 172 onthe table 174 prepared for a surgical procedure are shown. Positioned onthe rail 176 is a first surgical equipment holder apparatus 178 having afirst central surgical equipment holder 182 attached to the firstsurgical equipment holder apparatus 178. The first surgical equipmentholder apparatus 178 is attached to the sternal ascender apparatus 10 atthe first adapter channel 46. On an opposite side of the table, a secondsurgical equipment holder apparatus 180 is attached to an opposite rail,which is not visible here. The second surgical equipment holderapparatus 180 has a second central surgical equipment holder 184attached thereto and is also attached to the corresponding secondadapter channel on the sternal ascender apparatus 10 on its oppositeside, not visible here. Each of the first central surgical equipmentholder 182 and the second central surgical equipment holder 184 can beutilized to position and hold one or more pieces of surgical equipmentor tools such as the sternal ascender apparatus 10 or alternativelyscope holders, cannulas, or other surgical implements during a minimallyinvasive or other surgical procedure. In this configuration, the firstcentral surgical equipment holder 182 and the second central surgicalequipment holder 184 are shown bridging over the patient 172 in order tofirmly position the sternal ascender apparatus 10 in an initialcentralized location relative to the patient 172 on the table 174.

FIGS. 9A-9D are a series of perspective views illustrating operationalsteps of the use of the sternal ascender apparatus in a surgicalcontext. In FIGS. 9A-9D, portions of the patient 172 are shown incross-section and portions of various instrumentation are removed fromview for the purposes of clarity. The patient 172 is shown prepped for asurgical procedure, having an incision 186 made at just below thexiphoid process at the sternal notch, near the sternum 188. The sternalelevator apparatus 10 is secured onto the first central surgicalequipment holder 182 and the second central surgical equipment holder184, which are firmly mounted onto the operating table 174. The upperrack housing 48, or the arch keystone is at the top of the toothedlinear rack and thus enables subsequent movement of the rack 34 upward.The angle of the indicator handle 22 and therefore the sternal ascender12 has been adjusted by pressing the pivot button or pressable switch 30on the indicator handle 22, allowing movement of the indicator handle 22relative to the linear actuator gear 34. As shown in FIG. 9B, the distalend 12D of the sternal ascender 12 is inserted in direction 190 into theincision 186 until the sternal ascender 12 is in a desired locationalong the sternum 188. The sternal ascender 12 is aligned with theanatomy of the sternum 188 by using the depth indicator 27 to gauge thelocation of the tip of the panel of the sternal ascender 12 within thechest. At this point, the first central surgical equipment holder 182and the second central surgical equipment holder 184 are locked andsecured into place after proper adjustment. FIG. 9C illustrates theswivel bar 50 being unlocked and moved counterclockwise 192 to raise thesternal ascender 12 and indicator handle 22 in direction 194, whichapplies retraction to the sternum 188 and creates the subxiphoid space198 for access. A final state of this described procedure is illustratedin FIG. 9D, at which time the swivel bar 50 can be moved to a full up ordown position to lock the gear housing 48 in place to prevent anyfurther movement of the sternal ascender 12.

Various advantages of a sternal ascender assembly have been discussedabove. Embodiments discussed herein have been described by way ofexample in this specification. It will be apparent to those skilled inthe art that the foregoing detailed disclosure is intended to bepresented by way of example only, and is not limiting. As just oneexample, although the end effectors in the discussed examples were oftenfocused on the use of a scope, such systems could be used to positionother types of surgical equipment. Various alterations, improvements,and modifications will occur and are intended to those skilled in theart, though not expressly stated herein. These alterations,improvements, and modifications are intended to be suggested hereby, andare within the spirit and the scope of the claimed invention. Thedrawings included herein are not necessarily drawn to scale.Additionally, the recited order of processing elements or sequences, orthe use of numbers, letters, or other designations therefore, is notintended to limit the claims to any order, except as may be specified inthe claims. Accordingly, the invention is limited only by the followingclaims and equivalents thereto.

What is claimed is:
 1. A sternal ascender assembly, comprising: a panel assembly, wherein a first portion of the panel assembly is configured to engage a portion of a patient's ribcage during a procedure; an indicator handle extending from a proximal end to a distal end along a handle axis, wherein a first portion of the indicator handle is configured to be grasped by a surgeon during the procedure, and wherein a second portion of the indicator handle is coupled to a second portion of the panel assembly; a linear rack extending from a first end to a second end along a rack axis, the second end of the linear rack being coupled to a third portion of the indicator handle, the linear rack comprising a plurality of teeth; and a housing movably coupled to the linear rack, the housing comprising a cylindrical gear configured to rotate relative to a portion of the housing, a portion of the cylindrical gear engaging a portion of the plurality of teeth of the linear rack to displace the linear rack relative to the portion of the housing when the cylindrical gear is rotated.
 2. The sternal ascender assembly of claim 1, wherein the first portion of the panel assembly is an elongated support portion that extends from a proximal end to a distal end, and wherein a mounting post extends from the proximal end of the support portion such that the second portion of the panel assembly is a portion of the mounting post that is configured to be removably coupled to the second portion of the indicator handle.
 3. The sternal ascender assembly of claim 2, wherein the support portion extends from the proximal end to the distal end along a support portion axis, and wherein the mounting post extends along an axis that is substantially normal to the support portion axis.
 4. The sternal ascender assembly of claim 3, wherein the handle axis is substantially parallel to the support portion axis.
 5. The sternal ascender assembly of claim 1, wherein the second end of the linear rack is coupled to the distal end of the indicator handle.
 6. The sternal ascender assembly of claim 5, wherein the second end of the linear rack is pivotably coupled to the distal end of the indicator handle.
 7. The sternal ascender assembly of claim 6, further comprising: a pawl coupled to a fourth portion of the indicator handle; and a fixed indexing gear coupled to a portion of the linear rack, wherein the fixed indexing gear is configured to interface with the pawl such that when one or more teeth on the pawl intermesh with one or more corresponding teeth of the fixed indexing gear, a position of the linear rack is locked relative to the indicator handle.
 8. The sternal ascender assembly of claim 7, further comprising a switch coupled to the indicator handle and configured to defeat the pawl allow the fixed indexing gear to turn freely relative to the indicator handle.
 9. A sternal ascender assembly, comprising: a panel assembly, wherein a first portion of the panel assembly is configured to engage a portion of a patient's ribcage during a procedure; an indicator handle coupled to a second portion of the panel assembly, the indicator handle comprising a grip portion that is configured to be grasped by a surgeon during the procedure; a pawl coupled to a first portion of the indicator handle, the pawl including one or more teeth; a linear rack extending from a first end to a second end along a rack axis, the second end of the linear rack being coupled to a second portion of the indicator handle, the linear rack including a engagement portion; a fixed indexing gear including one or more teeth, the fixed indexing gear being configured to engage the pawl coupled to the first portion of the indicator handle such that when all or a portion of the one or more teeth of the pawl intermesh with all or a portion of the one or more corresponding teeth of the fixed indexing gear, a position of the linear rack is locked relative to the indicator handle; and a housing movably coupled to the linear rack, the housing comprising a gear that is rotatably coupled to a portion of the housing and engages a portion of the engagement portion of the linear rack to displace the linear rack relative to the portion of the housing when the gear is rotated, thereby displacing the indicator handle and the panel assembly relative to the portion of the housing.
 10. The sternal ascender assembly of claim 9, wherein the engagement portion of the linear rack is a plurality of rack teeth.
 11. The sternal ascender assembly of claim 10, wherein a portion of the gear engages a portion of the plurality of rack teeth of the linear rack to displace the linear rack relative to the portion of the housing when the gear is rotated.
 12. The sternal ascender assembly of claim 9, wherein the second end of the linear rack is pivotably coupled to a distal end of the indicator handle. 